Omitting content that is primarily valuable to experienced Haskellers is a feature, not a bug.
As an occasional Haskell user, I'm served much, much better by the existing site than by this new design. The existing one lets me get to the information I'm looking for with minimal effort. This new site denies me that accessibility, I'm afraid to say.
I don't see the point in trying to attract new users if doing so also means harming the experiences of established users. Drawing in new users becomes pointless if retention starts to suffer.
Newbies are going to head to haskell.org when they want to learn about the language, and it's sensible for them to be greeted by a pleasant introduction to the language.
As "an occasional Haskell user," you aren't the target audience for the haskell.org landing page. :) If you're visiting on a regular basis, there's no reason your needs couldn't be met by some page other than the landing page.
It's also reminiscent of what we saw with the iPhone, and nobody would say that the experience was much worse for users of previous smartphones. There are times when simplifying and giving structure to existing content just makes sense.
I'm curious, what content do you miss from the old page that can't be found in the Community or Documentation sections in the new design?
The purpose of a good landing page is not to serve as an index for all the content (that's what site maps are for), but to explain the concept and structure of the site to someone that haven't seen it before. The new page is much better in that respect.
I miss a link to the current Haskell wiki in the new design, but I definitely wouldn't expect to find a list of all the wiki pages on the land page, but available under the Documents section.
I want to be able to type "haskell.org" into any browser, and from there be able to quickly get to the standard library documentation, to the language spec, to Planet Haskell, to the downloads, and so on, without having to dig through subpages of subpages of subpages, and without having to scroll.
The Rust website at http://www.rust-lang.org/ is a good example of how a programming language home page should be laid out. There are many relevant links at the top. I can almost always find what I want within the first inch or two of the page. Yet it still shows all of the marketing junk for those who want that stuff, but it's placed well below the useful content.
The new Haskell design is the complete opposite of that. It puts a lot of useless junk front and center, and almost totally discards everything that actually is useful.